Forebyggelse af kondensdannelse ved udtagning af papir fra lavtemperaturmagasiner
Preventing condensation in the application of cold storage
A qualitative literature review on the preservation benefits of cold storage showed that when preserving paper the lifetime is doubled for each 5° C drop in temperature. By halving the relative humidity in the environment one can more than double the lifetime of the paper. To investigate the changes in temperature and relative humidity during transport in and out from cold storage several experiments where conducted. The experiments where carried out at The Royal Library in Denmark’s cold storage at Njalsgade 112. During the transport in and out from The Royal Library’s cold storage the changes in temperature and relative humidity where measured near the surface of the hollow test book and inside the book and inside a book placed in a stack of books. Based on the literature study and results from the experiments the following precautions, for transporting paper in and out of cold storages, to prevent condensation were taken: It is recommended that paper is stored in cold storages at temperatures down to 2° C, which exploits the low temperatures during winter, and about 45% RH. During transport out from the cold storage paper should be packed in an impenetrable packaging or acclimatized in a climatecontrolled room. During transport back to the cold storage it is recommended that paper be acclimatized in a climate-controlled room and not under any circumstances packed in an impenetrable packaging. A single book should be acclimatized for three hours in order to avoid condensation on the surface as well as inside and the books should be stacked separately during acclimatization in the climate-controlled room. It is also recommended that the Library prolong delivery time so that the necessary time is available to avoid condensation damage during transport in and out from the cold storage and that the books are digitized for expanding public access to the material and to limit the damage caused by physical handling of the objects and the risk of damage during transport in and out of cold storage.